Formatted Title
Modeling Study of Vapor Recovery Flow Requirements for High-Temperature Thermal Remediation
Background/Objectives
Vapor recovery rates for high-temperature (greater than the boiling point of water) in situ thermal remediation (ISTR) sites are typically set via rules of thumb, based on experience from other kinds of sites that may have very different physical situations. The absence of groundwater within a high-temperature ISTR site and the lack of a water table are two of the most obvious differences. These fundamentally different conditions may lead to the choice of vapor extraction rates that differ significantly from the most optimal value, resulting in unneeded energy inputs and/or oversized aboveground treatment equipment. Furthermore, few high-temperature ISTR sites have been implemented, leading to a paucity of real-world data. The objective of this study is to develop a model of contaminant mass recovery from high-temperature in-situ thermal remediation sites that can be used to explore optimal vapor recovery rates for differing site conditions.
Approach/Activities
The model development consists of the following steps:
- Construct an accurate conceptual model of contaminant mass vapor recovery from high-temperature sites, working from first principles,
- State this model in mathematical terms;
- Construct a numerical model simulating contaminant mass recovery from high-temperature sites;
- Use this model to explore design parameters and optimal vapor recovery rates for differing site conditions and varying input parameters.
Results/Lessons Learned
Model results are analyzed for varying site conditions. Parameters varied include permeability, temperature, contaminant vapor pressure, and vapor recovery rate. Implications for in situ thermal remediation design are identified and discussed.